In order to improve a viewing angle dependency of a γ characteristic of a liquid crystal display device (e.g. to prevent excess brightness on a screen), there has been proposed a liquid crystal display device (based on a pixel division system. See Patent Literature 1 for example) in which a plurality of sub-pixels in one pixel are controlled to have different luminance so that area coverage modulation of the sub-pixels allows displaying a half tone.
In the active matrix substrate described in Patent Literature 1 (see FIG. 38), three pixel electrodes 121a-121c are provided in one pixel region in such a manner as to be along a source bus line 115, a source electrode 116s of a transistor 116 is connected with a contact electrode 117a, the contact electrode 117a and a control electrode 511 are connected with each other via an extraction line, the control electrode 511 and a contact electrode 117b are connected with each other via an extraction line, the contact electrode 117a and a pixel electrode 121a are connected with each other via a contact hole 120a, the contact electrode 117b and a pixel electrode 121c are connected with each other via a contact hole 120b, the pixel electrode 112b which is electrically floating overlaps the control electrode 511 via an insulating film, and the pixel electrode 121b is capacitance-coupled to each of the pixel electrodes 121a and 121c (capacitance-coupling pixel division system). Further, an auxiliary capacitor electrode 512 is provided so as to be adjacent to the control electrode 511 in a row direction (direction in which a gate bus line 112 extends). The auxiliary capacitor electrode 512 is connected with the pixel electrode 121b via a contact hole 513. At a portion where the control electrode 511 and the auxiliary capacitor bus line 113 overlap each other, a retention capacitor between the pixel electrodes 121a and 121c and the auxiliary capacitor bus line 113 is formed. At a portion where the control electrode 512 and the auxiliary capacitor bus line 113 overlap each other, a retention capacitor between the pixel electrode 121b and the auxiliary capacitor bus line 113 is formed.
In a liquid crystal display device including the active matrix substrate, each of sub-pixels corresponding to the pixel electrodes 121a and 121c can serve as a bright sub-pixel and a sub-pixel corresponding to the pixel electrode 121b can serve as a dark sub-pixel. Area coverage modulation of the two bright sub-pixels and the one dark sub-pixel allows displaying a half tone.